To delimit the existing entry 01.01.1990 - 31.12.9999,normally I would use the delimit button but I couldnt see the delimit option in V_511_B. How do I go about delimiting 01.01.1990 - 31.12.9999 record and create new permissibility options from 01.10.2013? Please can you advise?

According to notes I made many years ago, if you need to amend permissibilities in V_511_B from a future or particular date, first delimit the entry in V_T511, ie create a copy of the existing entry from the date you require. I hope this still applies - worth a try?